My new Sierra...

Ok, shes not new....but since i added AAM 4.11 gears its like a new truck! The stock gears were 3.23. Had originaly planned on 3.73 gears but I am glad I did the 4.11 after Darryel at Lloyds showed me some other GM trucks he had done with 4.11 and even some 4.88 gears.

I sold my Superchips programmer and had a guy do a custom tune so it looks like i need to update the tune...my speedo is off 15-20 mph Also when my GPS hits 75mph my speedo is at 100mph and the truck backs off the power so I am guessing we set the speedo limit at 100mph.

My RPMS at at 2300 at 75mph so it looks like at 80-83mph my rpms should be ok with the Over Drive.

Lloyds DriveTrain in Tucson did the work for me - $653 out the door..he even painted my drums for me.

Nice! When you update the tune, you can fix the speedo. Just get a tuner that allows you to adjust gear ratio. I installed 4.56's with 35 inch tires and I used the Hypertech speedo calibrator and my speedo is not 1mph different than my GPS.

Hhaha...I havent tried yet...the shop said I should give it a 500 mile break in period. He also mentioned that the truck has a OEM type posi....well not really a posi per se...however he said they tend to break easily. Lockup or lockout something or another,